Indoor air pollution is an ever increasing problem. Recent studies by the Environmental Protection Agency indicates that humans are exposed to air pollutants indoors at levels which may be from 2 to 5 times to as much as one hundred times higher than outdoor levels. Since many people spend as much as 90% of their time indoors, this is a particular concern.
Increase in air pollution indoors is due at least in part to modern construction of more tightly sealed buildings and reduced ventilation in order to save energy. The use of synthetic materials for buildings and furnishings has further contributed to the increase in indoor air pollutants.
Of course, the most effective treatment to clean air is to remove the source of the pollutant. A second treatment is to improve the ventilation in the area, assuming clean outside air is available to reduce or remove polluted air. A third treatment method is an air cleaner. A number of air cleaners are on the market presently. These products not only add fragrants to the air, but also add air pollution. Air fresheners of conventional commercial formulations cover up the odor with a more powerful smell. Sometimes, these air fresheners include materials which block the nose from smelling anything. Offending gases are not removed from the air.
There are thousands of identified gases and particulants that pollute the air we breathe. Some of these include smoking odors, pet odors and odors from bathrooms and kitchen, musty smells, housecleaning products, pesticides, personal care products, kerosene and wood stoves. Industrial and automotive emission of gases also cause pollution.
There are presently four methods of cleaning the air which are available on the market. These include mechanical filters, electronic air cleaners, ion generators and chemical air cleaners. Mechanical filters can, of course, be installed in air ducts near the furnace and/or air conditioning units. Alternatively, they may be portable units which force air through a filter. This is suitable for removing large particles, but generally has little effect on odors.
Electronic air cleaners use an electrical field to trap charged particles. Again, they may be pan of a HVAC system or maybe a separate portable unit. Electronic air cleaners are typically electrostatic precipitators in which particles are collected on a series of flat plates. This equipment can remove some odors and particles from the air, although effectiveness varies. There is some concern by medical experts that the charged particles that are created during electronic air cleaning may become air borne and enter human lungs. Some have said that charged particles may be carcinogenic.
Ion generators also use static charges to remove particles and gasses from the air and are located in portable units. Many of these units produce ozone, the gas which charges the particles. Again, particles may be deposited on lungs and could be dangerous while not really removing a large percentage of the particles in the room.
The remaining method, chemical air cleaning, operates by attracting positive ions to the chemical which absorbs and takes out the air borne pollutants and other gasses. It is believed by some medical experts to be safer than electronic or ion generating units.
One chemical composition which is useful for air freshening is described in GRIMSHAW, et al U.S. Pat. No. 4,663,081. GRIMSHAW, et al disclosed a liquid composition for freshening air via a wick which supplies a liquid to a surface. The liquid contains twenty to seventy percent water and eight to thirty percent perfume. GRIMSHAW, et al discloses that certain solid compositions having water up to about four percent by weight.
DUMAS, U.S. Pat. No. 4,810,690 describes a non-flammable air freshener using forty to sixty-five percent of organic solvent and fifteen to fifty percent of water. Again, this is a liquid wick evaporator and concern is expressed for premature blocking of the wick.
Finally, DICKERSON, et al, U.S. Pat. No. 5,047,234, describes and air freshener composition of the aqueous type in which the formulation remains liquid. Inorganic metal salts are taught as being effective to enhance emulsion stability for these liquid positions.
At the present time, none of the air cleaner compositions previously known are completely successful in removing pollutants from the air. Accordingly, it is an object of this invention to provide an improved formulation for an air cleaner composition.
Another object of this invention is to provide a solid air cleaner composition.
Yet another object of this invention is to provide an air cleaner composition which comprises at least 70 percent by weight water based on the total weight.
Other objects will appear hereinafter.